Modulating interfacial polymerization by combination of organic phase additives and trimesoyl chloride for preparing high-performance thin-film nanocomposite reverse osmosis membranes

• Published in: Desalination 2024-12, Vol.592, p.118157, Article 118157
• Main Authors: Zhang, Tengfang, Wang, Peijian, Chen, Yuhao, Niu, Q. Jason, Sun, Haixiang
• Format: Article
• Language: English
• Subjects: Desalination; Interfacial polymerization; Organic phase additives; Thin-film nanocomposite membrane
• ISSN: 0011-9164
• DOI: 10.1016/j.desal.2024.118157

Incorporating hydrophilic nanoparticles into organic phase during interfacial polymerization (IP) to establish covalent bonds with organic phase monomers has proven to be a successful approach for fabricating high-performance thin-film nanocomposite (TFN) reverse osmosis (RO) membranes. However, the effect of covalent bonds number on the membrane structure and properties remains uncertain. Herein, hydrochloric acid doped polyaniline (PANI-HCl) with a small amount of amine groups and inherent polyaniline (PANI-base) nanomaterials with a larger amount of amine groups were prepared as organic phase additives for preparing high-performance TFN RO membranes. The amine groups on the nanoparticles can bond covalently with the acyl chloride groups of trimethyl chloride (TMC), leading to the accumulation of TMCs at organic/aqueous interface and accelerates IP reaction rate, resulting in a thinner, denser polyamide layer with more leaf-like structures and free volume. The water permeance of the PANI-base-RO membrane was improved by 62.5 % from 0.8 to 1.3 Lm−2h−1bar−1, and the NaCl rejection was improved from 97.6 % to 99.4 % compared with the pristine membrane. Overall, this work highlights the beneficial impact of organic phase additives with more amine groups on enhancing the desalination performance of RO membranes, providing valuable insights for the structural design of additives and dispersing medium selection. •Thin-film nanocomposite (TFN) reverse osmosis (RO) membranes performance was improved by adding organic phase additives.•The organic phase additive can covalently react with trimesoyl chloride (TMC) to form pre-bonds.•TMCs were carried by pre-bonds to the oil-water interface promoting interfacial polymerization reactions.•The effect of the covalent bonds number on the structure and performance of TFN RO membranes was thoroughly investigated.